Blood and other bodily fluids are sent in large quantities to medical laboratories where these fluids are processed and tested for diagnostic and other purposes. In order to minimize cost for such testing, the equipment and procedures utilized to process such samples are becoming increasingly automated so as to permit the procedures to be performed as quickly as possible with minimum labor. Further, since blood and other bodily fluid are now classified as hazardous substances, there are also safety reasons for minimizing handling of such specimens by people and for assuring that people do not come in contact with such samples.
The most popular way currently utilized for collected blood samples is to utilize a container, such as a glass tube, which is evacuated to be at relatively low pressure and is sealed at its open end with a rubber stopper or other puncturable seal. To draw a blood sample into the tube, one end of a double-ended needle is inserted into the patients vein and the other end of the needle is inserted through the stopper of the collection container, the partial vacuum inside the container drawing blood from the vein into the container.
When such blood filled containers arrive at the medical laboratory for testing, several procedures have heretofore been followed in processing the containers. Typically, the container is first "spun down" until all of the blood cells have settled to the bottom of the tube, leaving a layer of plasma or serum on top. The container may then have the stopper/seal removed and be placed in a sample rack for further processing, or the container may be unsealed and the plasma decanted into a cuvette or other open container for further processing. However, these procedures have several drawbacks. First, removing the seals is difficult to do automatically and is time consuming and expensive to do manually. Further, since the container is usually still under reduced pressure, there will be a sudden surge of air into the container when the seal is removed which can cause splashing of blood, something which is undesirable in all circumstances and is particularly undesirable when the process is being performed by a person because of the danger of contact with infected blood samples. Finally, the samples being in an open container exposes the samples to potential contamination in the laboratory, and the integrity of the samples can be better maintained if they remain in their sealed container.
For this reason, various schemes have been proposed for permitting aspiration of blood samples or other bodily fluid samples from the sealed container in which such samples are collected and shipped. However, these schemes also have limitations. For example, some such schemes have a sharp tipped probe pierce the seal to remove the sample. However, such probes tend to core the seal, which can result in the aspirating probe needle becoming plugged, thereby inhibiting aspiration of fluid from the container, and can also inhibit resealing of the container when the probe is removed, which resealing may be desirable in situations such as where the container may continue to be used for sample storage. Various schemes for preventing coring involve placing the needle opening on the side of the needle or otherwise deforming the needle opening. However, such schemes result in fluid from the needle coming out at an awkward angle when the fluid is to be dispensed, significantly complicating the design of the laboratory system.
For this reason, other schemes have utilized a canula shaped so as to minimize coring to puncture the seal, and have then passed an aspirating probe through the canula into the container to withdraw a desired quantity of fluid. These schemes also present a number of potential problems. First, the canula, being relatively large can abrade the rubber stopper, even if coring does not occur, causing rubber fragments which may be drawn into the probe with the plasma, potentially plugging the probe and destroying the precision and integrity of the samples. Second, the canula presents a temporary opening in the container seal through which contaminants may enter the container. Finally, the use of the canula limits flexibility as to how a number of containers on a rack, cassette of the like may be sampled. In particular, it may be desirable to take a first sample from all of the containers of a given group for a particular test, and to then go back and take a second sample from each such container for a subsequent test. However, these systems envision the canula remaining in the stopper for the entire test, and not being removed and reinserted. Therefor, unless a number of canulas are provided, something which is generally not feasible, all samples required from a given container must be taken before the canula is removed from the container and inserted in a subsequent container.
Finally, one scheme involves using a piercer to form an opening or cut in the seal and then passing a needle or probe into the container through the cut to aspirate or otherwise access the fluid. While this scheme overcomes some of the limitations of the procedures discussed earlier, it also has limitations. In particular, it can leave a ragged opening or cut in the seal, resulting in seal fragments as debris which can potentially clog the probe or adversely affect the integrity of samples. Further, where samples are being taken from multiple containers, as would be the case in a medical laboratory, the containers are preferably mounted close together in a rack and are not secured in the rack. The spacing between the piercer and probe in the prior art system limits how closely the containers can be mounted and no effective way is provided for stripping the piercer/probe from the seal for a loosely/rack mounted container.
Another potential problem with all of the above schemes is that, at some point during the handling of the container, blood cells or other debris from the sample may accumulate under the stopper. Since it is desired that only the plasma or serum be utilized for most tests, blood cells in a specimen may contaminate the specimen, rendering the test less valid. Such blood debris may also be misinterpreted by electronic level sensing modules frequently used in such systems, resulting in the improper collection or aspirating of the fluid. None of the current schemes adequately deal with this potential problem.
Another problem not fully dealt with in the prior art is the need to quickly, but effectively wash and dry both the piercer and probe between samplings so as to prevent any contamination of successive samples by these elements. Other improvements in design are also required to facilitate high speed operation, with at least four accessing operations a minute, while permitting accurate, contamination free operation and minimizing maintenance problems.
A need therefor exists for an improved method and apparatus for collecting blood or other bodily fluids from sealed containers or otherwise accessing such containers either to collect a desired fluid or other substance therefrom, to sample or sense properties of the substance contained in the container, or to dispense material into such container. Similar needs can exist when accessing other fluids from a sealed container such as closed sample vials on chromatography samplers or quality control sampling of any materials packaged in containers with rubber stoppers.